Does a repeated benign aspirate change the risk of malignancy after an initial atypical thyroid fine-needle aspiration?

Repeated fine-needle aspiration of the thyroid is sometimes recommended after an atypical diagnosis. However, histologic follow-up for patients with a benign second aspirate is limited. I reviewed the results of all thyroid aspirations with repeated aspirations and surgical resection for the last 13 years at Baptist Hospital, Miami, FL, and Homestead Hospital, Homestead, FL, and combined these with the results of intraoperative cytology and the literature. During the period, a total of 7,089 cases were aspirated and 1,331 resections were performed. There were 6 (1.7%) of 361 false-negative cases. Relevant intraoperative cytology was available for 24 cases. The order of the diagnoses (benign then atypical, atypical then benign) did not significantly affect the risk of malignancy (15% and 9%; P = .30). Patients with an atypical and benign diagnosis had a risk of malignancy (15%) higher than a single negative aspirate (3%; P < .001) and lower than that of patients with a single atypical diagnosis (27%; P < .001). Repeated aspirates are not independent events. Patients with a benign diagnosis after an atypical diagnosis have a risk of malignancy between the risks of a single benign or atypical diagnosis. Cytologists should strive to better communicate this risk.